The present invention relates to a combined integral molding technique between plastic materials, and particularly to a structure of a combined integral molded product of a pre-molded member requiring watertight property and airtight property.
An electronic device part having a connector portion for electrically connection to an external system has a plurality of wiring terminals in the connector portion. Therefore, there is a problem that the wiring is broken due to a resin pressure at a time of integrally molding the wiring with a resin.
In order to prevent the breaking of the wiring due to the resin pressure, as employed in an LSI package, there is frequently employed a wiring of a lead frame configuration structured so as to fix each of the wires by connecting an outer peripheral portion of the wires.
However, even in the case of employing the wiring of lead frame configuration described above, a rigidity of the wires becomes low when a cross sectional area of each of the wires becomes small. Therefore, there is generated an increased possibility that the wiring is broken due to the resin pressure upon integral molding. In order to prevent the breaking of the wiring due to the resin pressure, it is possible to consider a forming method in which each of the wires is fixed by pre-molding the wiring at a low resin pressure and an area on which the resin pressure is applied at an insert-molding.
As a semiconductor apparatus having the above described structure that the wiring is pre-molded, there is a structure that a terminal arrangement is fixed by pre-molding terminals for connection to an external system, as shown in JP-A-8-148642.
As described above, in order to prevent the terminals from being broken, it is effective to employ the structure in which each of the terminals is fixed by pre-molding and thereafter the pre-molded member is integrally molded with a polymeric material. However, the pre-molded member molded with the polymeric material has a significantly low heat conductivity in comparison with a metal material employed in a metal mold. Therefore, a cooling speed of the integrally molding resin becomes slow in a boundary portion between the pre-molded member and the integrally molding resin. The boundary portion tends to be a final cooled portion of the integrally molding resin. Therefore, a void is generated in the boundary portion due to shrinkage till the integrally molding resin is solidified, and a peeling or separation between the pre-molded member and the integrally molding resin is easily generated. Due to the void and the peeling or separation, airtight property and watertight property are deteriorated. As a result, there is generated a problem that it is impossible to satisfy a product specification such as a reliability.
Accordingly, an object of the present invention is to provide a structure which can keep airtight property and watertight property of an electronic device part even in the case that a void and a peeling or separation are generated at a time of using a pre-molded member of wiring and integrally molding the pre-molded member.
In order to achieve the above described object, in accordance with the present invention, there is provided a structure which can keep an airtight property and a water-tight property of an electronic device part even when a void and a peeling or separation are generated, by integrally molding a pre-molded member with an integrally molding resin in a state that a resin portion of the pre-molded member except a portion necessary for fixing the pre-molded member within a metal mold is surrounded by the integrally molding resin.
Further, it is possible to prevent the void and the peeling or separation from being generated by forming a recess in the integrally molding resin near the pre-molded member, in order to increase a cooling performance of the integrally molding resin, at a time of integrally molding the pre-molded member.